An ultra-low-power digitally programmable gain amplifier for biological applications

This paper presents an ultra-low-power digitally programmable gain amplifier for biological signal processing applications. To achieve low-power consumption, the MOS transistor operating in weak inversion region is used. The circuit is constituted by a class-AB current amplifier which can handle wide input signal. The gain of digitally programmable gain amplifier can be maintained by using digital signal levels. The proposed circuit is simulated using 0.5 μm CMOS process from MOSIS. The proposed circuit consumes 44.3 nW from ±1.2 V power supply. The programmable gain varies linearity from 0 to 16 dB through a 3-bit digital signal while achieves the total harmonic distortion -36.7 dB.